This invention relates to an improvement in self locking trays and deals particularly with a tray formed of paperboard or the like which may be erected into a tray formation without requirement of staples, adhesives or other means for securing the corners of the tray together in a permanent fashion.
With the advent of the fast food era, the requirements for a semi-permanent tray have flourished. The requirements generally are that a tray be capable of assembly from a carton blank by a non-skilled worker instantly. Preferably, the carton must be assembled without the use of any pre-gluing or stapling to make the completed tray a functionable device.
More and more manufacturers are shipping products which are packaged in craftboard containers and bound together with a colourless plastic membrane on pallets. In most instances, groups of cartons are collated on trays on the pallets before being bound together.
As the retailer receives the pallets of products, usually the retailer will continue to use the collating tray to keep the products of the same type together on the display shelf in an attempt to provide product impact on the consumer.
When all the products displayed on the trays have been purchased, the retailer may provide the tray for the use of customers in removing merchandise from the premises on the tray. At times, it would be convenient for the retailer to be able to "knock down" the tray to its original flat shape for ease of storage until required in future. If, for instance, the tray was erected using a heat setting glue, it is almost impossible for a retailer to "knock down" such a carton and subsequently re-erect it at a later date.
Examples of prior art devices are Canadian Patents 1,137,050 issued Dec. 7, 1982, 1,041,968 issued
Nov. 7, 1989, 890,780 issued Jan. 18, 1972, 885,859 issued Nov. 16, 1971 and 726,024 issued Jan. 18, 1966. Each of the above patents teaches a tray that may be constructed from a carton blank by suitable manipulation of the various parts of the carton blank.
Most of the prior art trays require a considerable amount of manual dexterity to assemble the final tray from the paperboard blank. Some of the blank designs require an inordinate amount of paperboard to construct the completed tray.
Prior art trays having narrow side walls have exhibited problems with panel stabilization because the sidewalls are too narrow to secure the slotted flaps. This tray overcomes this problem and will be quite rigid in its constructed form.
Difficulties with prior art designs can be found not only during the construction of the completed tray from the carton blank, where it maybe difficult if not impossible to be able to assemble the completed tray, but if time is a factor, it may be found that the prior art trays are only partially assembled so that the corner joints tend to bulge outwardly forming an awkward corner joint which may spontaneously disassemble delivering the contents to unintended locations.